In recent years, there has been a trend that the heating amount of a semiconductor chip increases as the function and the speed performance of a Central Processing Unit (CPU) and the like in an electronic apparatus have been advanced. In most cases, the semiconductor chip is not mounted on a large system board. In general, the semiconductor chip is mounted on a small board called a package board. A package board on which a semiconductor chip is mounted is called a semiconductor package. The semiconductor package is mounted on, for example, a print wiring board that is called a system board or mother board.
When the semiconductor package is mounted on the print wiring board in the above-described manner, a heat radiation mechanism such as a heat sink is mounted on the semiconductor package so that the heat from the semiconductor chip is released into the air. In this case, a heat spreader that touches the surface of the semiconductor chip is provided in the semiconductor package. In this manner, there is a proposed technique for effectively transferring the heat of the semiconductor chip to the heat sink by allocating the heat spreader between the semiconductor chip and the heat sink. The heat spreader includes a leg part extending toward the package board. The tip of the leg part is bonded to the package board using adhesion bond such as a resin, for example.
Regarding the above-described semiconductor package, the semiconductor chip may be jointed to the heat spreader with a joint material. For example, a metal joint material such as solder is used as the joint material used to joint the semiconductor chip to the heat spreader.
The followings are reference documents.    [Document 1] Japanese Laid-open Patent Publication No. 2010-205919    [Document 2] Japanese Laid-open Patent Publication No. 2005-12127    [Document 3] Japanese Laid-open Patent Publication No. 2003-60132